The
SRD seems to serve near-opposite purposes under the
GSL and the
OGL.
The 3.x-era
SRD was a listing of open content that you could use with very few restrictions. Things that were not in the
SRD but were in Wizards' books were considered closed content and could not be republished under the
OGL. This included some things that Wizards claimed as product identity, such as the Beholder and Mind Flayer.
Now, the new
SRD is something different entirely. It is a list of references that you can make to content in Wizards' books. There are specific limits in the
GSL as to what you can and can't do with those references. There is nothing in the
GSL - as far as I can tell - that limits what you can say about things left out of the
SRD.
Oddly, though, Wizards left things that it had considered product identity under the
OGL out of the
SRD... and I didn't see any product identity references in the
GSL. Is there anything stopping me from publishing under the
GSL and, say, redefining the Beholder? If there is, I am missing it...
-Stuart